Process of removing and recovering metal coatings from-metallic bases



(No Model.) I

' T. G. HUNTER.

PROCESS OF REMOVING AND REOOVERING METAL COATINGS PROM,

METALLIC BASES.-

I No. 529,864. Patented Nov. 27, 1894.

E NORRIS erms PHOTO-LITHD. wAsumomu o c UNITED? STATES? PATENT OFFICE.

THOMAS G. HUNTER, OF PHILADELPHIA,- PENNSYLVANIA.

PROCESS OF REMOVING AND RECOVERING METAL COATINGS FROM META'LLIC BASES.

SPECIFICATION forming part of Letterslatent N 0. 529,864, dated November 27, 1894.

Application filed January 30, 1894- Serial No. 498,455. (No specimenal To all whom it may concern:

Be it known that I, THOMAS G. HUNTER, a citizen of the United States, and a resident of the city of Philadelphia and, State of Penn,- sylvania, have invented a certain new and useful Process of Removing and Recovering Metal Coatings from Metallic Bases; and I do hereby declare the following to be a full, clear, and exact description thereof, reference being had to the accompanying drawing, form- 'ing part of this specification.

My invention has relation to the treatment of metals consisting of a base of sheet metal and a coating of alloy, or other metal, for the purpose of separating the two metals and reclaiming them in their separate conditions.

In Letters Patent of the United States, No. 511,846, issued to me January 2, 1894, l have described and claimed a process for removing tin from scrap, referring in the process to the employment of sulphate of copper as the active agent. My present application pertains to the same class of invention,'and has for its object the reclaiming and separating of combined metals consisting of a base of one metal and a coating of-another metal, or alloy, for commercial purposes, and which can be operated upon large quantities of metal at a comparatively small cost.

In the composition of soluble neutral compounds the metal contained or carried therein operates to exclude or occupy the place of hydrogen, as for example should sulphuric acid (H SO be employed, the presence of the hydrogen would prevent the operation of the acid radical upon the metal coating of the material to be operated upon in the process hereinafter described because of the greater affinity of the sulphuricvacid radical for the hydrogen than for the metal coating. It is therefore necessary that the soluble neutral compound (containing the acid radical), to be employed as the active agent in my process, shall contain a metal or material which practically excludes the hydrogen, and which, at

the same time, shall have less affinity for the acid radical than the coating metal of the combined metal scrap to be operated upon. I have also simultaneously filed applications for Letters Patent of the United States for improvements in the process of removingand recovering metal coatingsfrom metallic bases,

I Serial Nos. 498,453 and 498,454, in which the active agents employed belong to a difierent general class from those specifically noted in the present application.

In carrying out myinvention I employ any of themeutral salts of copperincluded in the organic acids radical, such as for instance acetate of copper, tartrate of copper. Of the organic acids I preferably employ acetate of copper.

Where, as an illustration, the coated metal to be operated upon is what is known as tin scrap and the metal to be removed is tin and the base iron, when acetate of copper is used, the tin having a greater affinity for the acid radical of the acetate of copper, the copper will be at once precipitated and the acid Will attack the tin until the tin is all removed and held in solution as acetate of tin, which tin in turn will be precipitated by the iron forming, with the acid radical, acetate of iron.

The following formula shows chemically the component parts of the acetate of copper as well as of tartrate of copper. As a matter of illustration :-Acetate of copper Cu,(0 H 0 Tartrate of copper OuO H O In the accompanying drawing I have illustrated one form of apparatus by which my invention may be carried into effect, although it will beunderstood that any other suitable apparatus may be employed, my invention residing in the process described.

In the drawing, F represents a suitable tank, preferably of wood, having an open top and provided at its lower end with a valved discharge, f. At a short distance above the bottom of the tank is a basket or grate, G, having vertical side bars, g, terminating at a point above the top of the tank in eyes, g, to which hoisting chains, it, maybe attached to remove the grate from the tank, when necessary. The grate, G, and bars, g, are preferably constructed of gun metal, or metal which will not be acted upon by the acid.

which water is supplied in the flushing operation hereinafter. described. At a point below the tank, F, is a supply tank, K, having an upper open end, while preferably at various levels on one or more sides are taps,

, Z, through which the contents of the tank may be discharged. This tank is adapted to re .Above the tank is a valved pipe, I, through having a greater affinity for the acid radical.

of the said compound than the metal contained in the compound, it is attacked by the acid radical, and the metal previously contained in solution, having less affinity for the acid radical, is immediately precipitated to the bottom of the tank. After a time the coating is entirely removed and held in solution, whereupon the metal comprising the base of the metal operated upon having a greater affinity for the acid radical is attacked by the acid and the metal previously held in solution is precipitated in the metallic form. \Vhen all the metal previously forming the coating metal has been precipitated the liquor and the precipitated metals are drawn off from the tank, F, through the trough or pipe, M, to the tank, K. By subsequently flooding the tank, F, with Water all the remaining particles of metal are washed to the bottom of the tank, F, when the water and remaining precipitate is drawn ofi, as before, tothe tank, K. The grate, G, which may, if desired, be provided with sides to form a cage, or basket, is then removed by the hoisting ropes or chains, h, and the metal forming the base removed. The precipitated metal contained in the tank, K, is removed therefrom after the liquor has been drawn ofli' from said tank.

In the drawing I have shown steam supply pipes, s, surrounding the cage, or basket, in which the tin is contained, so that, if necessary, heat may be used to facilitate the operation, said pipes being composed of any metal which the solution will not attack.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, isr 1. The process of separating a coating metal from the coated article, the coating metal of which is more electro-positive than the base of the soluble compound employed in the process and the metallic base metal is more electro-positive than its coating, said process consisting in subjecting the coating metal to the action of a salt of copper, the acid radical of which having a greater affinity for the coating metal than for its base, thereby precipitating the metal originally held in solution, the coating metal taking its place in the solution as herein described.

2. The process herein described of recovering metal coatings from a metallic base wherein the metal coating to be treated is more electro-positive than the base of the soluble compound employed in the process and the metallic base metal is more electro-positive than its coating, said process consisting in immersing the coated metal in a soluble salt of copper radical, thereby precipitating the metal of the compound in which the combined metals to be treated are immersed by the greater affinity of the coating metal for the acid radical of said compound, dissolving the coating metal and holding the same in solution, subsequently precipitating the said coating metal by the greater affinity of the metal base for the acid radical.

3. The herein described process of removing metal coating from its base wherein the metal coatingto be treated is more electropositive than the base of the soluble compoundemployed in the process and the metallic base is more electro-positive than its coating, said process consisting in subjecting the coating to the action of a neutral solution of acetate of copper, and permitting such action to continue until the copper and the coating metal have been precipitated in metallic form.

4. Theherein described process of treating tin scrap consisting in subjecting the tin to the action of a neutral solution'of a compound salt of copper having an organic acid radical and permitting such action to continue until the metal of the solution and the tin have been precipitatedin metallic form.

5. The herein described process of treating tin scrap consisting in subjecting the tin to the action of a neutral solution of acetate of copper and permitting such action to continue until the copper and tin have been precipitated in metallic form. 6. The processof treating tin scrap said process consisting in subjecting the tin scrap to the action of a neutral solution of acetate of copper, permitting such action to continue until the copper and tin havebeen precipitated and acetate of iron formed,then removing the precipitate with the acetate of iron, flushing the remaining iron and finally removing said iron.

In witness whereof I have hereunto set my hand this 29th day of January, A. D. 189i.

THOMAS G. HUNTER.

Witnesses:

J NO. E. PARKER, HORACE PETTIT. 

